Conventionally, a game image is generated by locating various game objects in a virtual game world so as to represent an image close to an image of the real world. An enemy object appears in the virtual game world as an adversary object against a player character operated by a player of the game. For example, as described in “Zeruda no Densetsu: Kaze no Takuto (The Legend of Zelda: The Wind Waker), Complete Guide”, composed by Michiru SHIBAHARA, written by Nui KURUWA, Yuichi KINO, Takashi FUNAKOSHI and Koki YONEDA, edited by Koichiro SHINMOTO, 1st. ed., (Enterbrain Inc.), Mar. 31, 2003, page 26 (hereinafter, referred to as non-patent document 1), action games in which a player character moves around in the virtual game world while defeating an enemy object and the like using an equipment item possessed by the player character (for example, a sword) have been developed.
The action game disclosed in non-patent document 1 proceeds with the player character performing a motion of slashing various game objects including the enemy object using the sword so as to defeat the enemy object which contacted the sword or cut off the game objects. Unlike a game in which a motion of using a sword is used only for attacking the enemy object, this action game enables the sword to be used for cutting off the game objects other than the enemy object and thus exerts a realistic influence on the game objects existing in the virtual game world. In this way, this action game provides the player with a new type of amusement, which makes the game more complicated and more entertaining.
However, in the real world, even when a motion of swinging a sword horizontally is performed on a mass of weeds, it is rare that all the weeds which contacted the sword are cut. Often times, many weeds which contacted the sword remain uncut. In addition, weeds, which are present at a periphery of the area in which the sword was swung and did not directly contact the sword, are waved in the swinging direction of the sword. By contrast, in the above-described action game, when a motion of swinging a sword is performed on various game objects including the enemy object, all the game objects are necessarily slashed after the motion is performed a predetermined number of times. For example, when a motion of swinging a sword is performed on weed objects, all the weed objects which are present in a valid area influenced by the motion are cut off after the motion is performed once. However, the weed objects outside the valid area are not influenced at all. Namely, the phenomenon in the action game is quite different from the phenomenon which can occur in the real world, and the player finds it unnatural depending on the object represented in the game image.
Therefore, a feature of certain exemplary embodiments is to provide a storage medium having stored thereon a game program for allowing an action of a player character to exert a more realistic influence on a game object in a virtual game world, and a game apparatus for executing such a game program.
Certain exemplary embodiments have the following aspects to attain the feature mentioned above. The reference numerals, step numbers (the term “step” is referred to simply as “S” and provided with the respective numerals), numbers of figures, and the like in parentheses in this section of the specification indicate the correspondence with the exemplary embodiments described later for easier understanding, and do not limit the certain exemplary embodiments in any way.
A first aspect of certain exemplary embodiments is directed to a storage medium having stored thereon a game program executable by a computer (30) of a game apparatus (3) for displaying a virtual game world, in which a player character whose motion is controlled by an input signal from an input device (6) in accordance with an operation performed by a player appears as well as a plurality of objects (OBJ), as a game image on a display screen (2). The game program causes the computer to execute a determination area setting step (S50), a collision detection step (S73), a first influence determination step (S75), a second influence determination step (S78), and a display state changing step (S80, S81). The determination area setting step sets a first collision determination area (C2) and a second collision determination area (C1) moving concurrently with the motion (D2a) of the player character. The collision detection step detects a collision of one of the first collision determination area and the second collision determination area against an object among the plurality of objects (contact of C1 through C2 with Cobj). The first influence determination step, each time the collision detection step detects a collision of the first collision determination area against an object, determines an influence, to be exerted on the object which has collided against the first collision determination area, as being one of a plurality of preset influences (cut off, waved, damage degree, no influence, etc.) at a predetermined probability. The second influence determination step, each time the collision detection step detects a collision of the second collision determination area against an object, determines an influence, to be exerted on the object which has collided against the second collision determination area, as being a predetermined influence. The display state changing step changes a display state of each of the influenced objects to a display state in accordance with the influence determined by each of the first influence determination step and the second influence determination step (FIG. 4, FIG. 7, FIG. 8).
In a second aspect based on the first aspect, the determination area setting step sets areas adjacent to each other as the first collision determination area and the second collision determination area.
In a third aspect based on the first aspect, the collision detection step includes a passing area setting step (S61). The passing area setting step sets a passing area (A2) in which the first collision determination area passes along with the motion of the player character before the motion is started.
In a fourth aspect based on the third aspect, the first influence determination step includes a probability determination step. The probability determination step determines the predetermined probability in accordance with the number of objects included in the passing area.
In a fifth aspect based on the fourth aspect, when the passing area includes a relatively large number of objects, the probability determination step determines a probability, at which the influence is determined as being a first influence (cutoff) included in the plurality of preset influences, to be relatively low; and when the passing area includes a relatively small number of objects, the probability determination step determines a probability, at which the influence is determined as being the first influence, to be relatively high (S62, S63).
In a sixth aspect based on the fifth aspect, the probability determination step determines the predetermined probability for each type of objects located in the passing area in accordance with the number of the objects of each type.
In a seventh aspect based on the third aspect, the first influence determination step includes a random number table determination step (S63). The random number table determination step stores, in a storage section (33), a plurality of random number tables (D2c, FIG. 13, FIG. 14) each describing an influence to be exerted on each object at a predetermined probability, and determines a random number table, among the plurality of random number tables, to be used for objects included in the passing area in accordance with the number of the objects. The first influence determination step determines an influence to be exerted on an object which has collided against the first collision determination area in accordance with the description in the determined random number table.
In an eighth aspect based on the seventh aspect, the random number table determination step selects a random number table to be used for each type of objects located in the passing area in accordance with the number of the objects of each type (S62, S63).
In a ninth aspect based on the first aspect, the determination area setting step further sets a third collision determination area (C3) moving concurrently with the first collision determination area and the second determination area and also with the motion of the player character (S54). The collision detection step further detects a collision of the third collision determination area against an object. The game program causes the computer to execute a third influence determination step (S79). The third influence determination step, each time the collision detection step detects a collision of the third collision determination area against an object, determines an influence, to be exerted on the object which has collided against the third collision determination area, as being a predetermined influence. The display state changing step changes the display state of each of the influenced objects to a display state in accordance with the influence determined in the third influence determination step.
In a tenth aspect based on the ninth aspect, the second influence determination step determines an influence, to be exerted on an object which has collided against the second collision determination area, as being a first influence included in a plurality of preset influences. The first influence determination step determines an influence, to be exerted on an object which has collided against the first collision determination area, as being the first influence at a predetermined probability. The third influence determination step determines an influence, to be exerted on an object which has collided against the third collision determination area, as being a second influence (waved) which different from the first influence.
In an eleventh aspect based on the first aspect, the plurality of objects include enemy objects each associated with a stamina value which decreases in accordance with a damage degree based on the motion of the player character. The first influence determination step determines an influence, to be exerted on each enemy object which is detected to have collided against the first collision determination area, as being a damage degree selected, at a predetermined probability, from a plurality of damage degrees to be subtracted from the stamina value. The second influence determination step determines an influence, to be exerted on each enemy object which is detected to have collided against the second collision determination area, as being a predetermined damage degree. The display state changing step changes the display state of each enemy object, which is detected to have collided against the first collision determination area or the second collision determination area, to a display state in accordance with a post-decrease stamina value obtained after the stamina value of the enemy object is decreased in accordance with the determined damage degree.
In a twelfth aspect based on the first aspect, the plurality of objects include enemy objects each associated with a stamina value which decreases in accordance with a damage degree based on the motion of the player character. The first influence determination step determines an influence, to be exerted on each enemy object which is detected to have collided against the first collision determination area, as being a damage degree calculated under a predetermined condition. The second influence determination step determines an influence, to be exerted on each enemy object which is detected to have collided against the second collision determination area, as being a predetermined damage degree. The display state changing step changes the display state of each enemy object, which is detected to have collided against the first collision determination area or the second collision determination area, to a display state in accordance with a post-decrease stamina value obtained after the stamina value of the enemy object is decreased in accordance with the determined damage degree.
In a thirteenth aspect based on the third aspect, the plurality of objects include enemy objects each associated with a stamina value which decreases in accordance with a damage degree based on the motion of the player character. When the passing area includes a relatively large number of enemy objects, the first influence determination step determines an influence to be exerted on each enemy object as being one of a plurality of preset damage degrees which decreases by a low degree at a relatively high probability; and when the passing area includes a relatively small number of enemy objects, the first influence determination step determines an influence to be exerted on each enemy object as being one of the plurality of preset damage degrees which decreases by a high degree at a relatively high probability. The display state changing step changes the display state of each enemy object, which is detected to have collided against the first collision determination area or the second collision determination area, to a display state in accordance with a post-decrease stamina value obtained after the stamina value of the enemy object is decreased in accordance with the determined damage degree.
In a fourteenth aspect based on the third aspect, the plurality of objects include enemy objects each associated with a stamina value which decreases in accordance with a damage degree based on the motion of the player character. When the passing area includes a relatively large number of enemy objects, the first influence determination step determines an influence to be exerted on each enemy object as being a damage degree which is calculated as decreasing by a low degree at a relatively high probability; and when the passing area includes a relatively small number of enemy objects, the first influence determination step determines an influence to be exerted on each enemy object as being a damage degree which is calculated as decreasing by a high degree at a relatively high probability. The display state changing step changes the display state of each enemy object, which is detected to have collided against the first collision determination area or the second collision determination area, to a display state in accordance with a post-decrease stamina value obtained after the stamina value of the enemy object is decreased in accordance with the determined damage degree.
A fifteenth aspect of certain exemplary embodiments is directed to a game apparatus for displaying a virtual game world, in which a player character whose motion is controlled by an input signal from an input device in accordance with an operation performed by a player appears as well as a plurality of objects, as a game image on a display screen. The game apparatus comprises determination area setting means, collision detection means, first influence determination means, second influence determination means, and display state changing means. The determination area setting means sets a first collision determination area and a second collision determination area moving concurrently with the motion of the player character. The collision detection means detects a collision of one of the first collision determination area and the second collision determination area against an object among the plurality of objects. The first influence determination means, each time the collision detection means detects a collision of the first collision determination area against an object, determines an influence, to be exerted on the object which has collided against the first collision determination area, as being one of a plurality of preset influences at a predetermined probability. The second influence determination means, each time the collision detection means detects a collision of the second collision determination area against an object, determines an influence, to be exerted on the object which has collided against the second collision determination area, as being a predetermined influence. The display state changing means changes a display state of each of the influenced objects to a display state in accordance with the influence determined by each of the first influence determination means and the second influence determination means.
According to the first aspect, each object as a target of an action performed by the player character (for example, an object to be slashed by a sword) is changed by an influence selected from a plurality of influences at a predetermined probability. Therefore, all the objects are not changed by the same influence. For example, in the case where the motion of the player character has an influence of cutting off the target objects, a state in which some of the objects are cut off but the other objects are not cut off can be represented. In addition, the virtual game world can include an area in which all the target objects are changed by the same influence by the motion of the player character and also an area in which the target objects are changed by an influence at a predetermined probability. For example, an area in which all the objects are cut off by the motion of the player character, and an area in which some objects are cut off but the other objects are not cut off, can be formed. Owing to this, the action performed by the player character in the virtual game world can exert an influence closer to the influence of the real world on the objects.
According to the second aspect, an area in which all the target objects are changed by the same influence by the motion of the player character, and an area in which the target objects are changed by an influence at a predetermined probability, can be adjacent to each other in the virtual game world.
According to the third aspect, a passing area in which the first collision determination area passes is obtained in advance. Therefore, the influence can be determined as being one influence at a probability in accordance with the state of the passing area in the virtual game world.
According to the fourth aspect, the probability is determined in accordance with the number of objects in the passing area. Therefore, the objects can be represented as being changed by different influences at a probability or cycle in accordance with the number of the target objects.
According to the fifth aspect, when the number of objects as targets of the motion of the player character is increased, the probability at which the first influence is exerted on each object is decreased. When the number of objects as targets of the motion of the player character is decreased, the probability at which the first influence is exerted on each object is increased. For example, when the player character attempts to cut a large number of objects at once, the number of objects which are cut is decreased. When the player character attempts to cut a small number of objects at once, the number of objects which are cut is increased. Owing to this, even when the player character performs a motion of cutting a large number of objects, the player character initially cannot cut all the objects. While the motion is repeated, the number of objects which are cut increases. Thus, the game provides the player with a sense of reality.
According to the sixth aspect, the probability is determined in accordance with the number of objects of each type located in the passing area. Therefore, the objects can be represented as being changed by different influences at a probability in accordance with the number of the target objects of each type.
According to the seventh aspect, the influence to be exerted on the objects is determined in accordance with a preset random number table. Therefore, the objects can be represented as being changed by different influences at a probability or cycle in accordance with the number of the target objects of each type.
According to the eighth aspect, the random number table is selected in accordance with the number of the objects of each type. Therefore, the objects can be represented as being changed by different influences at a probability or cycle in accordance with the number of the target objects of each type.
According to the ninth aspect, the virtual game world can include two areas in which all the target objects are changed by the same influence by the motion of the player character (the influence of each area may be different) and also an area in which the target objects are changed by an influence at a predetermined probability.
According to the tenth aspect, the virtual game world can include an area in which all the target objects are changed by the first influence by the motion of the player character, an area in which all the target objects are changed by the second influence, different from the first influence, by the motion of the player character, and an area in which the target objects are changed by the first influence at a predetermined probability. For example, an area in which all the objects are cut off by the motion of the player character, an area in which all the objects are agitated without being cut off, and an area some objects are cut off but the other objects are not cut off, can be formed.
According to the eleventh and twelfth aspects, the stamina value of each enemy object as a target of the action performed by the player character (for example, an enemy object to be slashed by the sword) decreases by a damage degree selected at a predetermined probability, each time the enemy object collides against the first collision determination area. For example, in the case where a plurality of enemy objects are targets of action performed by the player character, the enemy objects can be represented as being damaged at different degrees.
According to the thirteenth and fourteenth aspects, when the number of enemy objects as targets of the motion of the player character is increased, the damage degree to each enemy object is decreased. For example, when the player character attempts to slash a large number of enemy objects at once, the damage degree to each enemy object is decreased (the stamina value decreases by a small amount). When the player character attempts to cut a small number of enemy objects at once, the damage degree to each enemy object is increased (the stamina value decreases by a large amount). Owing to this, when the player character performs a motion of slashing a large number of enemy objects at once, the damage degree to each enemy object is decreased like in the real world. Thus, the game appears realistic.
A game apparatus according to certain exemplary embodiments provides substantially the same effects as those of the storage medium according to the exemplary embodiments described above.
These and other features, aspects and advantages of the exemplary embodiments described herein will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.